All architecture specific rwsem headers carry the same function
prototypes. Just x86 adds asmregparm, which is an empty define on all
other architectures. S390 has a stale rwsem_downgrade_write()
prototype.

Remove the duplicates and add the prototypes to linux/rwsem.h
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Acked-by: NTony Luck <tony.luck@intel.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: NDavid Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.970840140@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Instead of having the same implementation in each architecture, move
it to linux/rwsem.h and remove the duplicates. It's unlikely that an
arch will ever implement something different, but we can deal with
that when it happens.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: NDavid Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.876773757@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The rwsem initializers and related macros and functions are mostly the
same. Some of them lack the lockdep initializer, but having it in
place does not matter for architectures which do not support lockdep.

powerpc, sparc, x86: No functional change

sh, s390: Removes the duplicate init_rwsem (inline and #define)

alpha, ia64, xtensa: Use the lockdep capable init function in
       	     	     lib/rwsem.c which is just uninlining the init
       	     	     function for the LOCKDEP=n case
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: NDavid Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.771812729@linutronix.de>

The difference between these declarations is the data type of the
count member and the lack of lockdep in some architectures/

long is equivivalent to signed long and the #ifdef guarded dep_map
member does not hurt anyone.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: NDavid Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.679641914@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

All rwsem implementations include the same headers. Include them from
include/linux/rwsem.h
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: NDavid Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.483520950@linutronix.de>

Some nice improvements were made to rwsem in commit:

 424acaae
 rwsem: wake queued readers when writer blocks on active read lock

but this change overlooked that ia64 had defined RWSEM_WAITING_BIAS
as an unsigned value, while the new code required a signed value (as
it is in every other architecture).

This fix suggested by the original patch author: Michel Lespinasse.
Signed-off-by: NTony Luck <tony.luck@intel.com>

SPIN_LOCK_UNLOCKED is deprecated. Use __SPIN_LOCK_UNLOCKED instead.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: linux-ia64@vger.kernel.org
Signed-off-by: NTony Luck <tony.luck@intel.com>

After moving the the include files there were a few clean-ups:

1) Some files used #include <asm-ia64/xyz.h>, changed to <asm/xyz.h>

2) Some comments alerted maintainers to look at various header files to
make matching updates if certain code were to be changed. Updated these
comments to use the new include paths.

3) Some header files mentioned their own names in initial comments. Just
deleted these self references.
Signed-off-by: NTony Luck <tony.luck@intel.com>

Signed-off-by: NRobert P. J. Day <rpjday@mindspring.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

RWSEM_DEBUG used to be a printk based 'tracing' facility, probably used for
very early prototypes of the rwsem code.  Remove it.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add sem_is_read/write_locked functions to the read/write semaphores, along the
same lines of the *_is_locked spinlock functions.  The swap token tuning patch
uses sem_is_read_locked; sem_is_write_locked is added for completeness.
Signed-off-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We ran into the limit with the maximum number of waiters at one of our sites.

This patch increases the number of possible waiters from 2^15 to 2^31 by using
a long for the counter in struct rw_semaphore. S390 and alpha already do this.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Acked-by: NKenneth Chen <kenneth.w.chen@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!